Lubricating composition



Patented July 11,1944

. 2,353,586 A 7 a g g I LUBRICATING com'osmon V I Carl F. Prutton, Cleveland, and Albert KQSmith,

Shaker-Heights, Ohio, assignors, by nesne assignments, to The Lubri-Zol Development Corporation, Cleveland, Ohio, a corporation of Delaware No Drawing. limilication May 1.11940,

. Serial N0. 332,840 7 '2 Claims. (01. 252- 4) In' 'll'ks. Patents Nos 1,986,646 and 1,986,651 it 'is taught that the lubricating, properties of a lubricating composition may be materially improved and extreme pressure characteristics imparted to lubricants such as mineral lubricating, oil, by the addition thereto of minor amounts of This ap-.

halogenated carbon ring compounds. plication is a continuation-in-part of copending application Ser. No. 649,734 now Patent? No.

2,213,532, and also of copending application Ser. No. 241,606 now Patent No. 2,255,085, which is in turn a continuation-in-part of copending applications Ser. No. 31,720 now Patent No.,2,137,782, and Ser. No. 170,500, new Patent No. 2,204,620.

It has been explained that the reasonwhy such compounds thus improve the extreme pressure characteristics of the lubricant probably is duev to the fact that such addition agents chemically react with the bearing surfaces under the conditions imposed by relative movement and extreme pressure between the bearing surfaces to form a microscopic film of a metallic halide which prevents seizing between the bearing surfaces by acting as an anti-fluxing agent.

The halogenated carbon ring compounds were indicated as preferable in said patents due to the fact that such compoundsiare relatively stable, i. e., they do not readily hydrolyze in the presence of moisture which usually occurs in varying quantities in mineral oils. In other words, the halogenated carbon ring compounds are sumciently stable so that decomposition and attack thereof upon themetallic surfaces occurs only in the areas where extreme pressure is encountered, i. -e., on the bearing surfaces.

One theory of the action of halogen compounds, speciiically chlorine compounds, in ina creasing film strength, assumes that, as above-- indicated, under the stress of the rubbing action of bearing surfaces in motion under load, chloq rides of the bearing metals are formed on their surfaces and exert an anti-fiuxing effect in .preventing subsequent fusing of the two surfaces.

This urface, reaction, however, to take place with it eifectiveness depends upon the hydro-L the chlorine compound as a simultaneous lys intermediate reaction. These reactions may be expressed as follows: a

RC1+HzO=HCl-ROH M+HC1=MC1+H where R. is an organic radical and M is one of the metals of the bearing surfaces.

(Nora: The hydrogen evolved by (2) probably would act to reduce one or more of the organic compounds rather than to appear as-free hydrogen.) r V The correctness of the foregoing theory is subwhich is aromatic. As hereinafter more stantiated by the fact thatwhena chlorinated, hydrocarbon is added to a hydrocarbon mineral oil and the mixture thoroughly freed from moiss i' ture by the action of dehydrating ,agents, the; film strength is no more than that of the oil-1' alonei Exposure of the mixture to theiatmos phere so that it may absorb .a slightv amountoi moisturewill then cause anincrease in the-film strength.

Since the presence of a large amount of mois ture and especially of freewater is objectionable. in a lubricant besides being a highly variable fac-.

tor in normal service, it is advisable to.:,supplyi an oil soluble'substitutefor the same. I

It isthe principal object of thisinventiom therefore, to provide a lubricating composition as the type utilizing halogenated organic com-5 pounds as the extreme pressure-addition agent but so modified asto be effective in themanner defined without being dependent upon the pres-4eence in the lubricating composition of some. addiition material such as water.

Other objects of our invention the description proceeds.

To the accomplishment of the foregoing and related ends, said invention, then, .-consists' ,of the means hereinafter fully described and par-- ticularly pointed out in the claims;

The following description sets forth in detail T one approved combination of ingredients emsbodying our invention, suchdisclosed means C0111,

stituting, however, but one of various forms in which the principle of the invention may be used.

Broadly stated, this invention comprisesathe;

use as a lubricant either used alone orincorporated with any suitable oil base of halogen; bearing esters containing an aromatic nucleus, specifically esters of aromatic acids or esters pre- Y pared by esterifying anorganic acid with an aromatic alcohol,

The esters used in the lubricating compositions of 'thepres'ent invention may therefore be identified as of the type having the following reams 'where Q is either oxygen or sulphur, a: is atle t,

1, and R and R are of the class consisting of ,hydrogen and organic radicles, at least one of specifically pointed out, the esters of aromatic acids are the ones which will generally be found most useful.

addition agents, those which are ofthetype in which the o (hi I ill appear as Of the esters which may thus be employed 'as 2' I radicle is attached to a carbon'atom; which i a part of an open chain structure, are preferred.

This type 01' aromatic ester is more resistant to the hydrolyzing action of moisture which would tend'to cause the decomposition ci'other types of aromatic esters. for instance esters of phenolic compounds.

By the term "aromatic" wherever used herein,

we intend to include compounds containing a bcnzenoid structure including bensenoid structures other thanv the benzene ring, for example,

the pyridine, quinoline. thiophene, pyrrole and' furan structures.

Thusthe present invention is concerned wi the use of a particular'class of halogen-bearing" organic ringcompounds which also contain 1 oxygen. The above defined esters as class of halogen'and oxygen bearing organic ring com pounds are particularly desirablei'oruse as addition agents since they generally result in the production of an improved lubricant in which the characteristics suiting the same for use as a lubricant over a wide field ofapplication are generally improved;

' The ongen which is included inthe molecule of the addition agent acts to increase the effectiveness of the'latter in raising the fllm strength of a mineral oilto which the additionagent is added or to improve'the'lubricating properties of the halogenated compound when used without the addition of some other lubricant. The oxygen probably acts in thesame way as water in making possible the formation of hydrochloric acid as an intermediate step in the surface reaction above explained.

By combining in a single molecule the halogen and the ongen atoms, a lubricant is aii'ected in two ways:

First: The oxygen is always available at the" exact point where required; and

Second: The molecule is more strongly adsorbed by metal surfaces than similar halogen compounds which do not contain oxygen.

7 The lattercircu'mstance enhances the eife'ct of" I small amounts of such compounds because it is assasas Acetic acid derivatives:

Phenyl acetic'acid Diphenyl acetic acid stearic acid derivatives:

Phenylstearic acid Phenyl mercapto stearic acid xenyl stearic acid Naphthyl stearic acid Tolyl stearic acid Furoicacid Cinnamic'acid' Phthalic acid Toluic acid The alcohols combincdwith the foregoing arc-- matic. acids may either be aromatlcraliphatic.

or cycloaliphatic. Examples-ct such I alcoholsar's the following Methyl alcohol Ethyl alcohol Propyl alcohols Butyl alcohols Amyl alcohols Lauryl alcohols Cetyl alcohols Ben yl alcohol Furfuryl alcohol Tetrahydrofurfuryl alcohol Ethylene glycol Propylene glycol Di-ethylene glycol V Glycerol Erythritol Unsaturated alcohols. e. g.

Vinyl ethyl alcohol Allyl alcohol Crotonyl alcohol Oleyl alcohol Propargyl alcohol Cyciohexanol Methylcyclohexanol equivalent to an increase in'concentration of the compound at the bearing surfaces.-

The halogen and oxygen-bearing organic compounds of the aromatic ester type include compounds'of the aromatic type which may be classified as follows:

l. Esters of aromatic acids;

2. Esters formed by, the combination-0f an aromatic alcohol '(either mono-hydric or polyhydric) with an Organic acid which may be of the aliphatic, cycloaliphatic or aromatic type.

In'the following table are given examples of aromatic acids from which esters may be'prepared' as'representative of the class of compounds inchided in 1 above; I

Bcnzoic acid Benroic acid derivatives:

- Azobenzoic acid Thiobenzoic acids Mercapto benzoic acid Lauryl bensoic acid Salicylic acid Salicylic acid derivatives:

Thiosalicyllc acids Ethyl salicylic acid Heterocyclic acids:

Pyrrole carboxylic acids Thiophene carboxylic acids Amylcyclohexanol Phenyi cyclohexanol Cyclohexyl cyclohexancl The aromatic alcohols of-the'esters of class 2 above mcee-systole" following:

Benzyl alcohol Phenyl ethyl. alcohol Benzhydrol Tri phenyl carbinol Phenyl propyl alcohol Phenyl benzyl alcohol Furfuryl'alcohoi v Naphthobenzyl alcohol Cinnamyi alcohol The organic acids of the um n,

phatic or aromatic type used of esters inciuded'in classlab'ove may be any of the following:

Aliphatic acids, including: I

Saturated acids, suchas:

Acetic acid Prcpionic acids Butyric acids Lauric acids PaImitic acid Stearic acid Oxalic acid Citric acid Lactic acid Glycolic acid Malonic acid a,sss,sss

. such as:

Yinylacetic acid Vinyl acrylic acid vinyl slycolic acid Acrylic acid acid Oleic. acid Llnolenicacid Maleic acid Fuma-ric acid Linoieic acid Elaeostearlc acid: Propiolic. acid Stearolic acid erclo-flip t cacids, incl d s:

lilaphthenic acids 1 flel lwdrobenzoic, acid; Heterocyclic acids. including;

Ruroicacid carboxyiicacids Aromatic-acids, including V "I'hosegiven above in the list oi-aromaticacids ior'uselin the preparation of the esters oi class 1'. r

Inease where it is desired that the lubricant have a maximum stability, saturated compoundswill-usualLv-be preferred in, comparison with .unsaturated compounds. Where stabi1ity,jincludins the; to oxidation and polymerisation, knot of primary importance, certain of the unsaturated compounds may be preferred :ior-specia'l applications, for example to improve solubility, solventicityand the like. I

l'orcertain the ester may be used as addition agents in lubricating compositions of: the present invention. Such compounds may desirably contain an. oxygen bearingsubstituent, i. e. having oxygen present in a substituent' in addition to the oxygen present in the ester group. The following is a list of such oxygen bearing substituents which may thus be desirably included in the compounds which comprise the ad-' ditionagents oi the-present invention.

('I) Amide and substituted amith (8) Ether (9 Inorganic. radicies in whichthe oxygen is directly attached to a carbon atom: arsenite, ochlorite, phosphite, thiophosphate, thiophosphite, borate and hydroxy! amines.

Inorganic radicles in which theoxygen is indirectlyattached through the means of some other atom, e. g.: arsenate, chlorate, chlorite; cyanate, a hydroxylaminejni trate, nitrite, nitro, nitroso, oxime, perchlorate, phosphate, sulphate, j sulphite. sulphinic acid, sulphon'e', sulphonic-acid, sulphoxide, thiophos'phates, thiophosphites andthiosulphate.

In addition to the substituents containing oxy. gen, other substituents may also be present without destroying. and in certain cases, improving the eilect on thelubricating qualities of the oil; such as. other aryl groups, alkyl groups, and

amino and substituted amino groups, imino, aso, hydrazo, hydrazine, n'itrile, mercapto, sulphide, polysulphide, andthiocyanate.

Speciflcexamples-oi compounds 01 the various classes-described above are halogen derivatives 0! the compounds listed below. These derivatives may be substitution products, addition products, or both. They may be formed by halogenation of the compoundlistedor or intermediate compounds, or'bysome other method.

Amyl salicylate Benzyl acetate I Bensyl benl oate Benzyl mercapto stearate Benzyl naphthenate Benfll phenyl-stearate Benzyl stearate I Butyl' azobensoate Butyl esters oi:

. Pyrrole carbox'ylic acid 7 I Thiophene earhoxylic acid Butyl benzoate Butyl thio-bennoate Butyl ester of phenyl acetic acid Butyl ester of phenyl stearic acid Butyl mercapto benzoate Butyltoluate Esters of cinnamic acid, e. g.: Methyl andlauryl esters Dibutyl phthalate Esters oi diphenyl acetic acid, e. g.:

Methyl and lauryl eaters Ethyl ester or phenyl acetic acid Esters of ethyl salicylic acid, e. g.: Methyl and lauryi esters Ethyl toluate Methyl salicylate Methyl phenyl-stearate 1 Methyl toluate Esters of phenyl mercapto stearic acid, e. g.:

Methyl and lauryl esters Esters of phenyl propionic acid, e. 8.

Methyl and lauryl esters As a class oi esterswhich win be round par-v ticularly useful are the halogen bearin: esters derived ifmm an'acid formed by condensing an unsaturated acid such as those listed above with an aromatic compound such as:

, type are quite satisfactory for use- A s previously indicated, the foregoing so-called addition agents may, for most:uses, be added in minor amounts to otherlubricants such as mineral oil ilsh; oil, lard oil, castor oil, rape seed oil etc and in some cases-dependingupon the character of use, as well as the character of the selected agents, the latter may be effectively used intheirpurestate;

The. optimum amountof to be employed is usually dependent upon V8.11: ous considerations such as its cost, the character of the selected compounds, the character of the addition agent to which the same isadded and more particularly, the character. of the use to which the same is put. For most uses, since the. cost of such halogen compounds'is'usually con-1 siderably greater than lubricants such as min- ;the-halogen compound,

eral oil, optimum results are obtained byusing' minimum quantities of these halogenated addition agents. For the purpose of lubricating and reducing the friction between'relatively moving parts of an internal combustion engine such as crank case bearings, piston and cylinder surfaces,

as well as piston rings and valves, a composition according to our invention comprises amaj or pro portion of a suitable oil base'such as mineral oil and concentrations of from one-fourth of 1% to 2% of halogen compounds of the above defined.

type. If the valve structure-of the engine is to be lubricated separatelyfrorn the remainder of the mechanism by means acting in an auxiliary fashion such as by the additionof the lubricating composition to the engine fuel, the composition for such purposes will-preferably contain a larger amount of such halogen compounds, 1. e. from about2%toaboutl0%.

When lubricating bearing surfaces such as gears and the like where extreme temperatures are usually-not encountered a.- composition com-- prising a major proportion of a suitable oil base. and a total of less than about 20% of at least" one halogen and oxygen-containing organic compound of the enumerated class .will be found very satisfactory.

When combined with a lubricating oil such as mineral oil, the optimum amount of the halogen compound to be employed will depend largely upon the halogen content ,oflthe particular compound, its physical characteristics and especially its effect on the viscosity of the oil toiwhich it is added. When addition agentso: the above enumerated class having VeIy IOW viscosity are employed, and added to lubricants such as mineral oil, the limit of the amount. of. such compounds which may be-added and which will produce improved results depends in a largemeasure upon the reduction in viscosity of the .ucompositicn caused by the addition -,of'- such- :compounds. When, however, the more viscous compounds are employed, or where the particular use-does not require thick film lubrication, the so-ca'lled-addi tion agents may, as previously indicated-be employed in concentrations upto r With regard to the stabilityof the organic ring compounds contemplated, the most'resistant to hydrolysis of the halogen are thosein which the halogen is directly. attached to-an atom which-is part of a benzenoid ring structure. 1 Examples of suchring structures are aryl groups such as the phenyl and naphthyl groups. In any case, for

I most uses, it is preferred to have the halogenattached to an atom which is part'oi' 'aniorganic ring structure and especially'a siir-mernbered organicringstructure. r

' Thecompositions comprising our'inv entionl lavje certain advantages when used as a'lubricantof which the following may be mentioned:

First: By the use-of-this composition, it is possible to extend the pressure range between the bearing surfaces because ofthe reduced tendency for bearing surfaces "so lubricated to become scored or to seize at higherpressures than "are allowable with ordinary lubricants.

Second: The friction between thebearing surfaces is reduced', especially in the higher pressure range, below that obtained with ordinary lubricants. a

Other modes of applying the principle of the' invention maybe employed, change being made as regards the details described, provided the fe'a tures stated in any of the following claims cr the equivalent of such be employed.

We therefore particularly point out and distinctly claim as our invention:

1. A lubricating composition comprising a ma- Jor proportion of lubricating oil with theproperties of such composition affecting its use as a lubricant improved by incorporating therein a minor amount, based on the amount of lubricat.

ing oil, ofa stable oil-soluble halogen bearing ester of phthalic acid.

2. A lubricating composition comprising a ma- Jor proportion of mineral lubricating oil and a minor proportion of chlorinated di'butyl phthalate.

CARL F. rmrl'rors. ALBERT K. sm'rn. 

